Liquid level control device



June 10, 1952 v. KAGAY r 2,599,713

LIQUID LEVEL CONTROL DEVICE Filed June 28, 1946 2 SHEETS-SHEET l 111/I111, lrllrm 3mm Vcstal A. Kagag Jar-wis- L. Rob/sol? jdiZl/W anew;

June 10, 1952 v. A. KAGAY ETAL 2,599,713

LIQUID LEVEL CONTROL DEVICE Filed June 28, 1946 2 SHEETS-SHEET 2 JarvisL- Rob 50!? Patented June 10, 1952 LIQUIQ LEVEL CONTROL DEVICE} Vestal:Alli-agavand arvis It to isqn, Dal as Tern, assignors, .to Mei-la ToolCorporation,

Dallas, TeX- a corporation of Texas Applicationdune 28, 1946', Seria No.680,134 14 Cla ms. 1- Hid- 3.2)

This: invention relates; to new and useful improvements in liquid levelcontrol devices.

In petroleum wells which are incapable of'fl-owingthe, well liquids tothe surfacebecauseof insuflicient sub-surface formation pressureor forother reasons, it has becomethe general prac ticeto; utilize anauxiliary lifting fluid, such as gas or air, which fluid is introducedinto the well liquid column below the upper level thereof to aerateandlift said column to the surface The admission of the auxiliarylifting fluid is sometimescontrolled' by a series of flow valves whichare located at various elevallionswin the well conductor or tubingand'which are usually actuated by pressure, differentials thereacross,whereby the lifting fluid? is admitted as needed to the well liquid insaid conductor or tubing; the use of a series of flow valves is commonlyreferred to, as stagelift; Another type of flow device and one withwhich the, present invention is adapted for useis the intermitter devicewhich is simply a single valve. mechanism, for controlling, atpredetermined intervals, the admission of a lifting fluid into awellliquid column within a well conductor or tubing. Qrdinarily, theintermitter device is disposed at a predetermined elevationbel'ow' thelevel to. which the well liquids will normally rises in said conductoror tubing and, said deviceis intermittently actuated from the surfaceeither through a mechanically controlled, means, such as shown in thepatent to Stages No. 1,683,930 or by. the admission of a predeterminedauxiliary pressure in the annu lar space outside said conductor ortubing as shown in the pending application of; R.. O. Walton, Serial No.151,570, filed; July 20, 1942, now abandoned. When the intermitter isactuated, a predetermined volume of lifting fluid under pressurevadmitted, to the. liquid conductor or tubing and this, admitted fluid isin accordance with the well liquid which will normally be present. abovethe point of' admission of sai lifting fluid.

So long as the well liquids in the conductor or tubing rise to thenormal standing level or do not quite reach such level, the liftingoperation is. satisfactorily accomplished by the admitted lifting fluid.However, it has. been found that in many instances the well liquid levelwill rise higher than that normally expected and when this occurs, thelifting fluid admitted upon the subsequent operation of the intermitteris in= sufficient to lift or raise the liquids because the excessiveload is greater than that for which the intermitter device was set.

and which is so constructed that It is, therefore, one, object, of; the,presentin vention to 2 provide an improved liquid level con; troldeviceiwhich may be readily connected; in a well conductor or tubingand; which; will acpu rately control the level to which the well liqui swill rise in said conductor or tubing, h llflb qfi cient. operation ofan inter mitter type oflifting fluid control; device connected insaidconductor abovethe device, is assured,

An important object of; the invention is to pro;- vide an improvedliquid levelcontrol dcvicewhich is ac ua ed by the difiere tialb w ln.hemes; sureor load of, thelwell liquids acting on; one side anda knownpredetermined pressure on its op po; site side, whereby the, device isin a position perq mitting upflow through the. well conductor til such,time as the liquid reaches: a desiredlevel after which the device isactuated to shut qif u t p w; he d v e a a n eingr perated toallowiupflow when the liquid load thereabove is reduced by removal ofliquids upWdrdlythr ug-h the conductor.

Anotherobject, of the invention is to; provide an improved device forcontrolling the levelof the well liquids within a conductor or tubingwherein amain valve controls the. upward flow of the well liquids andwherein the. actuation of the main valve is, in turn, controlled by apilot valve which when open admits pressure to, the actuating parts ofsaid main valve; the pilot valve beingmovable in accordance with thedifie ferential in the. pressure of the liquid column above the assemblyacting on oneuside thereof and a fixed or known pressure. acting, on theopposite side thereof, whereby the pilot is opened to open the mainvalve and permit upflow of well liquidsonly when the liquid above theassembly is below the desired predetermined level."

Still another object of the invention is to provide an improved liquidlevel control device wherein the fixed or known pressure, which actsupon one side of the pilot to open the same when the well liquid levelis below the desired point, is utilized to open the main valvewherebyposn tive actuation of the main valve is assured.

A further object of the invention is to provide an improved liquid levelcontrol device, oi the character described, which is adapted to beemployed in combination with an intermittervalve the lifting fluid underpressure which is normally. admitted to the well liquid column by theintermitter for lifting the well liquids may be utilized to controlactuation of said liquid level control device.

The construction designed to carry out the vention will be hereinafterdescribed together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawing,wherein an example of the invention is shown, and wherein:

Figure 1 is a view, partly in section and partly in elevation of a wellconductor extending through a well bore and having a liquid levelcontrol device, constructed in accordance with the invention, connectedtherein,

Figure 2 is a transverse, vertical, sectional view of the liquid levelcontrol device, with the pilot valve as well as the main valve in closedor seated position,

Figure 3 is a view, pilot valve and main Figure 4 is an enlarged,

similar to Figure 2 with both valve in open position,

horizontal, crosssectional view, taken on line 4-4 of Figure 3,

Figure 5 is an enlarged, horizontal, cross-sectional view, taken on theline 5-5 of Figure 2,

Figure 6 is an enlarged, horizontal, cross-sectional view, taken on theline 6-45 of Figure 2,

and I Figure 7 is an enlarged, horizontal, cross-sectional view, takenon the line 1--1 of Figure 2.

In the drawings, the letter A designates a well bore having a wellcasing l0 therein. A well tubing ll extends downwardly through thecasing l0 and has its upper end supported in the usual casing head l2which is mounted on the upper end of the well casing. The lower end ofthe well tubing has the conventional well screen 13 through which thewell said tubing attached thereto. A suitable well packed M, which isschematically illustrated, packs off between the tubing and casing abovethe perforated screen, whereby the well liquids from the formation flowupwardly through the well tubing H.

Because of the lack of sub-surface formation pressure or for otherreasons, the well liquids do not flow to the surface but rather rise toa normal standing level L within the well tubing II." It has become thepractice in this type of well to employ an auxiliary lifting fluid, suchas gas, which lifting fluid is introduced into the annular space betweenthe well casing and well tubing through an inlet pipe 15. The admission2 of the auxiliary lifting fluid into this annular space may becontrolled by a suitable intermitter control mechanism I 6.

The admission of the auxiliary lifting fluid from the annular space intothe well liquid column within the tubing is ordinarily controlled by 'anintermitter valve B which is connected in the well tubing at some pointbelow the normal standing level, indicated by the dotted line L inFigure 1. The particular construction of the intermitter valve issubject to variation and any of the well known devices of this charactermay be employed. The particular valve illustrated in Figure 1 is thatshown in the hereinbefore referred to Walton application, Serial No.451,570.

However, it is pointed out that a mechanically controlled intermittervalve, such as shown in the patent to Staggs 1,683,930 could besubstituted for the valve.

In order for the valve B to function properly I upon each actuation toefiiciently lift the well liquids in the tubing above said valve, it isdesirable that the liquid level L be controlled for obviously if theliquid level rises to a height greater than that which the admittingauxiliary fluids are admitted into lifting fluid is capable of raising,inefilcient operation is had.

The present invention is directed to controlling the liquid level of thewell liquids as they rise within the well tubing and to maintain thislevel at a desired or predetermined point so that efflcient functioningof a suitable intermitter valve which admits the auxiliary lifting fluidmay be assured. In accomplishing the control of this liquid level, thedevice C, which constitutes the present invention, is connected in thewell tubing I I at a point below the intermitter valve B. This device Ccomprises an outer tubular housing which is constructed of a maintubular body 2! having a bushing 22 threaded into its upper end. Acoupling collar 23 connects the upper end of the bushing 22 with thewell tubing H. A somewhat similar bushing 24 is threaded into the lowerend of the tubular body 2| and has its lower portion coupled by acoupling collar 25 with the well tubing and thus it is obvious that theassembly forms a part of the tubing string.

As explained, the well liquids rise upwardly in the well tubing to thenormal standing level L and for controlling the flow through the tubing,the device C is provided with a main control valve 26. This valve ismovable within the bore 24a of the bushing 24 and is adapted to moveupwardly into engagement with a valve seat 21 which is formed in thelower end of a valve seat member 28. As is clearly shown in Figure 2 themember 28 which is threaded into the upper end of the bushing 24 has anaxial bore 29 through which the valve rod 30 of the valve 26 extends. Inaddition the member has flow ports or passages 31 which extendvertically therethrough. The upper end of the valve rod projects abovethe member 28 and has nuts 32 threaded thereon. The valve is normallymoved upwardly toward a seated position as shown in Figure 2 by a coilspring 33 which surrounds the valve rod and is confined between the nuts32 and the upper end of the member 28. A stop collar 34 having verticalpassages 35 therein is threaded into the lower end of the bushing 24 andlimits the downward movement of the main valve 26.

It will be obvious that when the main valve 25 is open a flow upwardlythrough the tubing past the valve into the bore Me of the tubular bodyof the device, then upwardly through vertical passages 221) formed inthe bushing 22 and finally into the tubing above the device, may occur;however, when the valve is in its seated position as shown in Figure 2,upward flow of well liquids through the tubing is prevented. In order tocontrol the liquid level it is necessary that the valve 26 be open toallow upflow through the tubing when the level is below the line L.Whenever the level L is reached by the well liquids the valve 26 closesto halt further flow of well liquids upwardly in the tubing II tothereby maintain said level.

For controlling the opening and closing of the main valve, a pilot valveassembly is mounted Within the device C and as shown in Figures 2 and 3this assembly includes a tubular sleeve 36 which has its upper endthreaded into the lower end of the bushing 22. A coupling 31 threadsinto the lower end of the sleeve and has an axial bore 38. A cylinder 39has its upper end connected to the coupling 3'! and a duplex piston 49is slidable within the cylinder. The piston comprises an outer sleevemember 4| and an inner plug member 42 which are capable of telescopingmovement with respect; toeachother; When pressure-- is applied to the.upper end of the piston through the bore: 38' of; the couplin thepiston. 40 is moved downwardly to engage the. upper end of the: valverod or stem and thereby force the main valve oif 'ofwits seatto an openposition. The use otthe duplex piston, that is, a piston. in. two partsis merely for-the. purpose of preventing said piston from sticking to.the wall of the cylinder. If the uppersection 4|. of the. piston shouldbecome: stuck within the cylinder; the pressure may pass through a port41a. in the upper end of said section and may act against the plugportion 42. of the piston to move this. portion. downwardly separatelyof the upper section and. thus. operation of the main valve could. stillbe effected. If the lower section 42 oithe piston becomes stuck,pressure applied to both this portion, as well as the upper section 4|,will affect release thereof. However, itis noted that any desired typeof piston could be employed, and it is desirable that the piston have arelatively sloppy or loose fitwithin its cylinder to allow a pressureleakage between the outer surface of the piston and the bore of thecylinder.

For controlling the admission of pressure to the piston 40, a pilotvalve 43 issecured to the lower end of a valve rod 44, which rod isdisposed axially within the tubular sleeve 36. The valve 43. is adaptedto engage a valve seat 45 to close an orifice 45a which extends throughthe valve seat member and which communicates with the bore 36 of the.coupling and thence with the, cylinder 39. above the. piston 49; Whenthe pilotvalve 43. is in its raised or unseated position the pressure ofthe lifting fluid in the annular space may flow through a radial porttill-formed ,in the upper bushing 22, then downwardly through the bore22a of said bushing, through the sleeve 36; past the pilot valve 43; andinto the cylinder 39v to exert its pressure on the piston. This resultsin adownward movement of the piston which engages the. valve rod or stem30; of; the. main valve to move said main valve to an open or unseatedposition. Obviously, when the pilot valve 43 is. closed, the coil springwill return the main valve and piston to their upper positions whichcloses said main valve, any pressure above the piston escaping throughthe leakage space between the outer surface of the piston and the wallof the cylinder; It is noted that the pressure of the spring 33 actingagainst the lower end of the piston. is sufficient to force any. fluidabove the pistonoutwardly around said piston.

The pilot valve is controlled in its actuation by a depressible bellows4! which is mounted within a tubular casing 48. The casing 48 has itsupper end connected to a plug member 49 which is supported on an annularshoulder 50 within the upper portion of the bushing 22, said plug beingretained in position by a coupling memher 5! threaded into the top ofsaid bushing. The upper end of the bellows 41- is connected to the plug49, while its lowerend is connected to a nut 52 which is secured on thestem 44 of the pilot valve. The pilot valve is constantly urged towarda. lowered or seated position by a coil spring which is confined betweenthe lower end of the casing 45. and an adjusting nut: 54 threaded on thelower portion of the pilotvalve stem 44.

It will be evident that when the operating bellows 4.1 is in itsextended position (Figure 2), the pilot valve is closed. However, whenthe bellows.. 4.1.: is collapsed or retracted, as; shown in Figure, the;ilot valve 43 is raised or in an unseated position to admitpressureto-the actuat ing piston 40. for themain valveZfi; Theexterlorof" the operating bellows is exposed to the pres;- sure of the auxiliarylifting fluid which is'in the annular space between the well casing andthe well, tubing, such pressure acting through the inlet port 46 in. thebushing 22, then through the bore 22a. of said bushing and through ports55 formed in the wallof the casing 48. Thus, the pressure of theauxiliary lifting fluid is constantly tending to collapse or retractthe. operating bellows and is therefore tending to unseat the pilotvalve. The interior of the bellows 41. is acted upon by the well liquidsin the well tubing I I above-the device, such liquids acting: downwardlythrough the axial bore 4.9a of'the plug 49 and the axial bore 5|a of thecoupling 5|. A suitable perforated pipe or screen 56' is threaded intothe coupling 5! and this screen. may be covered by a suitable protectiveshield 55! which has inlets 58 in its lower portion. Thus, the wellliquids in the tubing above the device may enter the inlets 58, thenpass through the screen 56, bores 5m and 49a and into the interior ofthe bellows. The well liquids which flow upwardly through the. tubularhousing 2| of the device may bypass the bushing through. the verticalpassages 2212 which are provided in. said bushing.

From the foregoing it will be obvious that the operating bellows 41 ofthe pilot valve is operated by the differential in the pressure of thewell liquids acting on the interior of the bellows and the pressure ofthe auxiliary lifting fluid in the annular space between thewelltubingand easing, acting upon the exterior-of said bellows. The particulardifferential at which the bellows is collapsed may be set by adjustingthe coil spring 53 which obviously adds its pressure to the pressure ofthe well liquids tending tohold the valve closed.

In the operation of the device, said device C is connected in the welltubing ll below the intermitter valve 13 and above the packer l4, Withthe desired auxiliary fluid pressure in the annular space outside of thetubing, the pressure of this tubing acts upon the bellows 4'! tocollapse said bellows and unseat the pilot valve 43, thereby admittingthis pressure to the operating piston 49, whereby said piston is moveddownwardly to engage the valve stem 30 and unseat. the main valve 2b.When this occurs Well liquids may flow upwardly through the tubing,thence through the device C, passing through thetubular housing 2| andvertical passages 22b of the bushing 22 into thewell tubing above thedevice C and also above the intermitter valve B. .The fluid load abovethe device C may act through the inlets 58 in the protective shield '51,through the screen 55, coupling 5| and plug 49 into the interior of thebellows. Whenever the liquid level rises to the point L, the load whichis acting on the interior of the bellows, plus the force of the spring53, is suificient to overcome the pressure of the auxiliary liftingfluid which is acting exteriorly of the bellows. When this condition isreached, the bellows is expanded to close the pilot valve 43 and shutoff the-pressure acting against the operating piston 43. As soon as thispressure is relieved, the coil spring 33 associated with the main valve26 may move said main valve upwardly to its closed position and preventthe further upflow of wellliquidswithin of the conductor,

7 the tubing. Therefore, the level L can never rise any higher until thefluid load above the device C is removed.

The removal of the fluid load is effected by actuation of theintermitter valve B which opens to admit auxiliary lifting fluid intothe well liq- .uid column. This admission of the lifting fluid into theliquid column will raise the well liquids to the surface and this willunload the tubing above the device C. As soon as this occurs, the

pressure acting interiorly of the actuating bellows 4'! is reduced, withthe result that the lifting fluid pressure acting exteriorly of saidbellows collapses the bellows to again open the pilot valve 53 and admitpressure to the operating piston. This again moves the piston iddownwardly to unseat the main valve 25 and allow upflow of well liquidsthrough the tubing. The main valve 26 will remain open until such timeas the liquid load above the device again expands the actuating bellowsto reseat the pilot valve.

It will be evident that the device will accurately control the level towhich the well liquids in the tubing may rise. Such control assures thatthere will never be a greater liquid load than the intermitter valve Bcan handle and in this manner emcient lifting or raising of the liquidsto the surface upon each operation of the intermitter is assured. It isagain noted that any suitable type of intermitter valve B may be em- 3ployed either a pressure actuated type or a me chanically controlledarrangement. Since the device C is actuated by a difierential in thepressure of the liquid load on one side and the auxiliary fluid pressureon the other side, the level to which the liquid may rise can beaccurately controlled.

The foregoin description of the invention is explanatory thereof andvarious changes in the size, shape and materials, as well as in the de-49 tails of the illustrated construction may be made, within the scopeof the appended claims, with out departing from the spirit of theinvention.

What we claim and desire to secure by Letters Patent is:

1. A liquid level control device including, a well conductor, a housingadapted to be connected in said conductor, a main valve within thehousing for controlling the flow of well liquids through the housing andupwardly through the well conductor, and a, pilot valve within thehousing for controlling actuation of said main valve, said pilot valvebeing operated by the differential in pressure between the well liquidload within the conductor above .the housing and a fixed fluid pressurewhich is present exteriorly whereby said pilot is opened to open themain valve when the pressure of the liquid load above the housing fallsbelow a predetermined point.

2. A liquid level control device including, a well conductor, a housingadapted to be connected in said conductor, a main valve within thehousing for controlling the flow of well liq; uids through the housingand upwardly through the well conductor, a pilot valve within thehousing for controlling actuation of said main valve,

an actuator connected to the pilot valve having well conductor, ahousing adapted to be connected in said conductor, a main valve withinthe housing for controlling the flow of well liquids through the housingand upwardly through the well coriductor, a pilot valve within thehousing for controlling actuation of said main valve, an actuatorconnected to the pilot valve having one side exposed to a fixedpredetermined pressure exteriorly of the housing and its opposite sideexposed to the pressure of the well liquids in the conductor above thehousing, whereby said actuator and the pilot valve are operated by thedifferential in such pressures, said pilot valve remaining closed tomaintain the main valve closed so long as apredetermined well liquidlevel is present in the conductor and being automatically opened to openthe main valve and admit additional well liquids to the conductor whensaid level drops below the predetermined point.

4. A. liquid level control device as set forth in claim 2, with aresilient means associated with the pilot valve for normally urging saidvalve toward its closed position, the force of said resilient meansbeing added to the pressure of the well liquid pressure, whereby thedifierential at which said valve operate may be predetermined.

5. A liquid level control device including, a well conductor, a housingadapted to be connected with said conductor and having a flow passagecommunicating with said conductor whereby well fluids flowing from theformation flow upwardly through said passage and conductor, a main valvein said passag movable to open and closed position for controllingupward flow of the liquids in said conductor, and means including apilot valve actuated in accordance with the level of the well liquids inthe conductor for controlling the operation of the main valve-wherebythe latter is opened only when the liquid level falls below apredetermined point.

6. A liquid level control device as set forth in claim 5, wherein thepilot valve of the main valve control means is operated by thedifferential in the pressure of the well liquid and a predeter v minedknown pressure exteriorly of the housing and conductor.

7. A liquid level control device including, a well conductor, a housingadapted to be connected with conductor and having a flow passagecommunicating with said conductor whereby well fluids flowing from theformation flow upwardly through said passage and conductor, a main valvein said passage movable to open and closed position for controllingupward flow of the liquids in said conductor, said main valve beingnormally in a closed position closing flow through the passage,pressure-actuated means for moving the valve to its open position, andmeans operated when the level of the well liquids in the conductor abovethe main valve falls below a predetermined point for admitting pressureto the pressure-actuated means whereby the main valve is opened topermit upflow of the well liquid to restore said liquid level.

8. A liquid level control device including, a well conductor, a housingadapted to be connected with said conductor and having a flow passagecommunicating with said conductor whereby well fluids flowing from theformation flow upwardly through said passage and tubing, a main valve insaid passage movable to open and closed position for controlling upwardflow of the liquids in said conductor, said main valve being normally ina closed position closing flow through th passage, pressure-actuatedmeans for moving the valve to its open position, and a pilot valve insaid housing for controlling the admission of pressure fiuid to thepressure-actuated means.

9. A liquid level control devic as set forth in claim 8, wherein thepilot valve is moved to an open position to admit pressure fluid to thepressure-actuated means to open the main valve only when the level ofthe well liquid in the conductor above the passage falls below apredetermined point.

10. A liquid level control device as set forth in claim 8, wherein apressure responsive actuator is connected to the pilot valve and alsowherein said actuator has one side exposed to a fluid pressureexteriorly of the tubing and its opposite side exposed to the pressureof the well liquids in the conductor above the passage, whereby saidactuator is operated by the differential in such pressures.

11. An apparatus for flowing wells comprising,

a well conductor, an intermitter control valve connected in theconductor and operable independently of the liquid level in saidconductor for controlling the admission of a pressure lifting fluid intothe conductor at predetermined time intervals, a liquid level controldevice connected in the conductor below said intermitter valve andhaving valve means for shutting off the admission of well liquid intothe conductor when the level of said liquid rises to a predeterminedpoint in the conductor, said valve means of the liquid level controldevice being normally urged toward a closed position, means forconducting the pressure from exteriorly of the conductor to the valvemeans to hold said valve means in an open position, and means actuatedby the liquid within the conductor rising to a predetermined level forshutting oil the application of pressure to the valve means to effect aclosing of said valve means.

12. An apparatus for flowing wells comprising, a well conductor, anintermitter control valve connected in the conductor and operableindependently of the liquid level in said conductor for controlling theadmission of a pressure lifting fluid into the conductor atpredetermined time intervals, a liquid level control device connected inthe conductor below said intermitter valve and having valve means forshutting oil? the admission of well liquid into the conductor when thelevel of said liquid rises to a predetermined point in the conductor.said intermitter control valve being actuated solely by the pressureexteriorly of the conductor and irrespective of the liquid present inthe conductor.

13. The combination with a well conductor having an intermitter controlvalve connected therein and operable independently of the liquid levelin the conductor for controlling the admission of a lifting fluid underpressure into said well conductor, of a liquid level control deviceconnected in said well conductor below said intermitter valve and havingmeans for maintaining the level of the well liquids at a desired pointin said conductor, said liquid level device including a main valve,pressure-actuated means for opening the valve, and a pilot valve forcontrolling the admission of pressure to the pressure-actuated means,said pilot valve being opened only when the level of the well liquid inthe conductor falls below a predetermined point.

14., The combination with a well conductor having an intermitter controlvalve connected therein and operable independently of the liquid levelin the conductor for controlling the admission of a lifting fluid underpressure into said well conductor, of a liquid level control deviceconnected in said well conductor below said intermitter valve and havingmeans for maintaining the level of the well liquids at a desired pointin said conductor, said liquid level device including a main valve,pressure-actuated means for opening the valve, a pilot valve forcontrolling the admission of pressure to the pressure-actuated means,and pressure responsive means connected to the pilot valve for operatingthe same, said pressure responsive means having one side exposed to thewell liquid in the conductor above the control device and its oppositeside exposed to the pressure exteriorly of the conductor, whereby thepilot valve is actuated by the differential in such pressures.

VESTAL A. KAGAY. JARVIS L. ROBIESON'.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

